Our casita was ready when we arrived, even though we had to arrive early due to some transportation issues. Our unit (Toucan) was really a very large studio, but it suited exactly what we needed. A king bed, a decent sized closet and a small kitchen with a table, stove and modest sized fridge, much larger than a dorm fridge but not a 25 cu ft unit. The stove was a full up four burner stove and oven. The stove worked fairly well but the burners were either on or off. The kitchen was well equipped with pots and pans and cooking utensils. There were a variety of plates, bowel, glasses and utensils there. I'd suggest a stop at either El Rey or Super 99 to get a few things like tea, coffee, butter and such. Get in, unpack and look at the kitchen. Call Dagoberto (or have Diana call him). Whatsapp is heavily used in Panama and is the best way to communicate. Use Google translate to cut&paste your requests and the replies. Taxis are cheap, $3-4 for most destinations. Uber is also available but not reliable as to when. There are a number of restaurants a short taxi away and some in walking distance.We rented a golf cart for a day but probably should have just used a taxi.
There's a washer there but the dryer is solar and wind powered, ie a clothes line. The water is fine and we had no concerns drinking it anywhere. At the grocery store buy local or pay 50-100% more for American brands, although some American brands are made locally.
Bring lots of $1 and $5 bills.